I’ve just re-read Paul Griffiths’ and John Wilkins’ inspiring paper on evolutionary debunking arguments (EDAs) for religion (it is a very influential paper on cognitive science of religion and evolutionary debunking, despite its not having appeared in print yet) for a chapter of a monograph I’m writing. Using Guy Kahane’s debunking genealogical framework, they argue that natural selection is an off-track process, i.e., one that does not track truth: it produces beliefs in a manner that is insensitive to the truth those beliefs. From this, they conclude that the beliefs that are the outputs of evolved systems are unjustified.
Causal premise. S’s belief that p is explained by X
Epistemic premise. X is an off-track process
Therefore, S’s belief that p is unjustified
When we apply this argument in a generalized manner, where X stands for “natural selection”, this looks like a bad strategy for the naturalist – ultimately, it leads to self-defeat in a Plantingesque manner that most proponents of EDAs would like to avoid. G&W’s position is more subtle: they don’t want to treat truth-tracking and fitness-tracking as competing explanations (as Plantinga seems to do), instead, they argue that fitness-tracking and truth-tracking operate at different explanatory levels. In many cases, tracking truth *is* the best way of tracking fitness, especially given (1) that cognition is costly (brains consume a lot of energy), (2) your beliefs influences how you will behave, (3) your behavior influences your fitness. They propose “Milvian bridges”, which link truth-tracking and fitness-tracking, in order to salvage commonsense and scientific beliefs.

The term Milvian bridge is coined in reference to Constantine’s victory at the Milvian Bridge, which was traditionally interpreted as evidence for the truth of his Christian beliefs, as he triumphed over his pagan opponents: Christianity was argued to be true because it was pragmatically successful. In this vein, they construct a Milvian bridge for commonsense beliefs, which are argued to be true because they are pragmatically successful (the Milvian bridge has some affinity with Reid’s philosophy and with the no-miracles argument in philosophy of science):
“Organisms track truth optimally if they obtain as much relevant truth as they can afford, and tolerate no more error that is needed to obtain it.”
For science, they propose an indirect Milvian bridge, as follows
“Given the Milvian bridge connecting commonsense to pragmatic success, we can justify the methods by which we arrive at our scientific beliefs. The reasons we have to think that our scientific conclusions are correct and that the methods we use to reach them are reliable are simply the data and arguments which scientists give for their conclusions, and for their methodological innovations. Ultimately, these have to stand up to the same commonsense scrutiny as any other addition to our beliefs. Thus, if evolution does not undermine our trust in our cognitive faculties, neither should it undermine our trust in our ability to use those faculties to debug themselves – to identify their own limitations, as in perceptual illusions or common errors in intuitive reasoning.”
For religion, by contrast, they think no Milvian bridge can be constructed, because the mechanisms that lie at the basis of religious belief are not truth-tracking. G&W consider some evolutionary accounts, for instance, that religion is the result of an overactive tendency to attribute agents to the environment. They write:
“The idea that religious belief is to a large extent the result of mental adaptations for agency detection has been endorsed by several leading evolutionary theorists of religion…Broadly, these theorists suggest that there are specialized mental mechanisms for the detection of agency behind significant events. These have evolved because the detection of agency- “who did that and why?”- has been a critical task facing human beings throughout their evolution. Religious belief has been jokingly described as “taking the universe personally”, and on this account, that is precisely correct. None of the contemporary evolutionary explanations of religious beliefs hypothesizes that those beliefs are produced by a mechanism that tracks truth. […] If the agency detection account is correct, then people believe in supernatural agents which do not exist for the same reason that birds sometimes mistake objects passing overhead for raptors. These beliefs are type one errors and they are the price of avoiding more costly type two errors.”
As Godfrey-Smith already wrote in his essay on signal detection, it would be totally pointless to have an agency detection system if it did not, at least sometimes, produced correct beliefs. So the system seems to be truth-sensitive (directed at detecting agents). G&W seem to acknowledge this, but argue that agency detection, while not truth-insensitive, is still off-track because it does not detect agents reliably. It generates an excess of false positives of the “better safe than sorry” kind, because the costs of failing an agent are higher than the costs of detecting an agent that isn’t there, the system will err at the side of safety and detect a lot of agents that aren’t there. G&W use this as a debunking strategy to argue that religious beliefs are unwarranted.
I have been thinking that the generality problem remains a big problem for EDAs against religion, and for EDAs against other complex cognitive capacities, such as our capacity to form moral evaluative judgments. For example, in the case of religion, if we grant for a moment that agency detection is responsible for the generation of religious concepts (ghosts, gods etc), at what level of generality should we consider the operation of this capacity? Under experimental conditions people are pretty good at detecting and identifying agency-like movements on computer animations (a lot of Heider and Simmel like studies show that people can make fine-grained distinctions about motions, e.g., playing, chasing, and even flirting. Remarkably, people are better at spotting living things on images than lifeless things: when they are presented with pictures of quasi-identical scenes and one little thing changed, they are more likely to spot what changed if it is an animal (e.g., a small pigeon) than if it is a conspicuous red truck or a building. So while there might be good theoretical reasons for expecting an error-prone, unreliable capacity to detect agents, there is to my knowledge no direct empirical support for this prediction.
Now sometimes agency detection does go awry, as when we hear wooden planks creak in an old house and form the belief that there’s a burglar in the house. But many more times, we form the belief that there is an agent, when there actually *is* an agent (e.g., when you see someone walking across the street from you on a clear day. When debunkers of religious belief appeal to hyperactive agency detection, they are already assuming that the agent that is being detected (e.g., God) is of the false-positive kind, the sound in the dark room. But I don’t see how they can assume this in a non-question begging sense.
And this problem becomes even more pressing if we consider that there are multiple evolutionary hypotheses on the origin of religious beliefs: some say it is an adaptive illusion to enhance cooperation (Wilson, Bering), others that it is the result of an intuitive distinction between the mind and body (Bloom), or a result of out propensity to attend to intriguing, counterintuitive ideas (Boyer). So, in order to run an EDA against religious belief, we would have to specify what of what type(s) of cognitive processes religion is a token. As long as this does not get cleared up – and given the imbalance of theory and empirical research in cognitive science of religion, it’s not going to be cleared up soon – we cannot do this in a rigorous, principled manner. Without this specification, we cannot say that religion is the result of unreliable (or more generally off-track) cognitive processes.

I think, in a related way, there is a grave danger of creeping teleology in these arguments, one that is not sufficiently recognized. When we look at hyperactive agency detection, for instance, anyone with common sense can see that what’s actually being described, functionally and structurally, could just as easily be called agency-candidate detection without any injustice to any of the facts on which the account is based. In order to get the objects of these ‘detection mechanisms’ sufficiently precise to be able to distinguish agents and agent-candidates as the object of detection, you have to be imbuing the entire system with an extraordinary amount of teleology. We can respond just as easily to something’s possibly being an agent as we can to its being an agent; indeed, we can do so even knowing full well that it probably isn’t actually one, and therefore without the belief. We have no reason whatsoever, for instance, to think that the birds mentioned in the example are mistakenly identifying overhead objects as raptors rather than correctly identifying them as objects with some obvious features shared with raptors without assuming that we know for sure that they are somehow set up specifically for one and not the other. This is a common problem with any sort of evolutionary debunking argument, whether for religion or for morality or for anything else; at the very least they would take a much more precise understanding of the actual evolutionary pathways than we have, but they seem even more than that to require a more robust teleology than any obvious evolutionary account of function could provide.

Indeed. If God doesn’t exist, then it isn’t “debunking”, it’s just explaining an error. And if God does exist, then there is nothing to debunk. Plantinga’s argument against naturalism gets its traction because if naturalism is true, then there is nothing to guide evolution â it’s undirected, random, i.e. it cannot be necessarily correlated with truth. On the other hand, if theism is true, then evolution can be directed or designed in such a way that it tracks truth. I’m also not sure how successful the “Milvian Bridges” can be: a bridge needs to be anchored on solid ground, and grounding a common-sense level of reliability is the trick. (Labelling Plantinga’s deliberately amusing example as “wacky” is not a convincing refutation.) It’s not surprising that given that foundation, we can build science on it, for that’s what science is. Of course, one can also use that same basic foundation to build religion. (I don’t know of any real religion which grounds itself in nothing more than “I sense things in the bushes”.)

It seems to me that the religious case isn’t particularly interesting.
Either God exists or not.
If God exists, then there is no difficulty in affirming that the processes are truth-tracking, because there is no difficulty in affirming that God designed the environment in such a way that there would be belief-forming processes that would lead creatures to believe in him.
If God doesn’t exist, then our most plausible theory will be that there are no supernatural agents at all. But if there are no supernatural agents at all, then it doesn’t really matter if the processes that generate religious beliefs are truth-tracking or not, since in neither case do they produce knowledge.
I think the more interesting cases are the truth-trackingness of the processes that produced our beliefs about morals, values, fundamental metaphysics, practical reasons and epistemic reasons.

Brandon:
“at the very least they would take a much more precise understanding of the actual evolutionary pathways than we have”
I think there are some cases where the story doesn’t require very precise understanding of the pathways. Consider the obvious evolutionary story about why we believe survival and reproduction to be worthwhile, for instance.
I want to emphasize, however, how striking it is that none of the debunkers I’ve read so far acknowledges that their argument needs to be taken as an argument for the disjunction of the claims: (a) we don’t have knowledge of M-type truths (moral, modal, metaphysical, axiological, etc.) or (b) there is a being who intentionally designed the evolutionary process to be truth-tracking in regard to M-type truths.

Suppose a naturalist were to produce the minutely detailed account of our physical evolution as a human species, a strictly mechanical evolution which has produced us with the specific cognitive faculties we have. Faculties according to which we have free will, which let us apprehend moral values, and which incline us to believe in God. Notice that this account is entirely naturalistic, i.e. there is no sign of a supernatural purpose-driven meddling in it. How is the theist to respond to this best possible state of epistemic affairs for naturalism? – I think the theist will point out that God, out of the myriad other naturalistic-friendly accounts which the indeterministic nature of physical reality permits, could certainly have actualized into reality this partricular one, which indeed comports with how God wishes the human condition and especially the human cognitive faculties to be.
Thomas Nagelâs review of Plantingaâs latest book which was recently discussed in this forum (here) holds that the theistic position vis natural evolution is that God âguidedâ evolution by âcausing appropriate mutations and fostering their survivalâ. I think this is not only a limited view but a misleading one, because it posits the physical universe as a self-existing unguided mechanism in which God here and there has reason to cause diminutive adjustments. Rather the correct theistic view is I think that God continuously actualizes the entire physical state of reality in a way which not only comports with general providence (which entails keeping up the natural order which the physical sciences study), but also with special providence (which entails the currying out of the free will of all persons, including of course Godâs). In other words there is no ontological difference between a genetic mutation that is taking place right now, or the forming of dew on a blade of grass, or the neurophysical analogue of the moral empowerment felt by someone in prayer, or my typing these words â they are all caused by God into becoming part of reality. In short: God did not specifically guide natural evolution; God guided and continues to guide all of creation.

“if naturalism is true, then there is nothing to guide evolution â it’s undirected, random, i.e. it cannot be necessarily correlated with truth.”
That’s awfully quick. If by “guide”, you have in mind some guidance by an agent capable for forming intentions and having plans, then you’re surely right that there’s no guidance if naturalism is true. (I’ll grant you that it’s not super-intelligent turtles designing us all the way down/back.) Understood in that sense, however, the undirected claim, the random claim, and the not necessarily correlated with truth claims don’t follow from the fact that there’s no guide (so understood). The causal processes that an agent might use to produce intelligent creatures with truth-tracking capacities can be divided up into the mental and non-mental parts of the process and the non-mental parts of the process would generate the same results even if we subtracted the mental bits out. If by “guide”, you don’t have in mind some guidance by an agent, but only a causal process that causally shapes the formation of our cognitive capacities, then you haven’t really offered an argument against naturalism at all. You’ve simply asserted that naturalism is random. I doubt that it is, but if you had an argument for that claim, I’d be interested to see what it was.

It seems to me that the following premise is presupposed by all the Plantinnga-type arguments against naturalism: (1) if evolution is unguided by a supernatural agent (in particular, by God), then we have no more reason to believe that our cognitive faculties are reliable than that they are not. They do not presuppose: (2) if evolution is unguided by a supernatural agent (etc.), then we have reason to believe that out cognitive faculties are unreliable. The consequent of the relevant conditional is skeptical about the reliability of our cognitive faculties; it does not say that they are unreliable. But I think that neither (1), nor (2) is true. What’s true, I think, is: (3) if evolution is unguided by a supernatural agent (etc.) AND there is no other reason to think that our cognitive faculties are reliable, then we have no more reason to believe that they are reliable than that they are not.
But from what DeCruz says of G&W’s argument, it seems that they are arguing that THERE IS other reason to think our cognitive faculties are reliable. The way I’d put it is that THE BEST EXPLANATION of the reproductive success of certain of our human ancestors is that for the most part they were guided by true beliefs that their cognitive faculties produced. Of course, IT’S POSSIBLE that those faculties produced false beliefs, and underlying non-cognitive mechanisms corrected the actions that would have been taken based on those false beliefs, with the result that these ancestors acted JUST AS IF they were acting on true beliefs. But that is not the best explanation of what was going on. So (3) cannot be used to show that naturalism (which holds that no supernatural agent guides evolution, let alone all of creation), leads to skepticism and self-defeat because the second conjunct of (3)’s antecedent is false. (1) and (2) cannot be used to show that either since they are themselves false. There is as yet no good argument to show that naturalism leads to skepticism and self-defeat.

Plantinga thinks that there are equally good alternative explanations. For instance (this is me, not Plantinga, but in his spirit) critters whose desires and beliefs were so wired up that they’d tend to do A when they believed that doing A does not promote something they desire. In such critters, it is false beliefs that would yield reproductive success.
One might question the possibility of this. Perhaps the for-the-most-part connection between desires and beliefs is analytic, so that there couldn’t be such critters. But maybe we can come with more clever hypotheses that don’t run into this.

Sure, it’s logically possible for there to be creatures that have false beliefs accompanied by correcting underlying mechanisms that lead to reproductive success. To allude to one of Plantinga’s favorite examples, a frog might have a false belief about where a fly is but have some underlying, corrective mechanism that makes his tongue hit the fly when he goes after it. But is it possible for anyone to rationally believe that this is the case if another hypothesis that only posits true beliefs will explain the fly’s success?
I think Hume believed that miracles are logically possible, but it is not possible for one to be justified in believing that a miracle has occurred solely on the basis of testimony. Regardless of whether Hume was right about this, it brings out the distinction between (A) it’s logically possible that P given evidence E, and (B) it’s logically possible to be justified in believing that P given evidence E. Other things being equal, the “reliable beliefs” hypothesis beats “the unreliable beliefs plus underlying corrective mechanisms” hypothesis for explaining reproductive success.

“But is it possible for anyone to rationally believe that this is the case if another hypothesis that only posits true beliefs will explain the fly’s success?”
Well, one doesn’t need to rationally believe that this is the case, but only that on the naturalistic hypothesis it is not significantly less likely than the non-perverse explanation.
One might think that the non-perverse explanation is simpler. But one gets the perverse explanation basically by taking the non-perverse one and replacing “true” with “false” in the story about the connection between belief and desire. Maybe “true” is simpler than “false”, but not by much. So the perverse explanation is only a little more complex, and hence only a little more probable. That won’t quite get Plantinga what he wants, but maybe it’s damaging enough to think that on naturalism it’s only a little more probable than not that we have reliability.
Besides all this, there may be an even more serious problem for a scientific explanation of reliability. It seems that any explanation of Reliability must make use of the predicate True, since Reliability is a claim about the truth of beliefs. But it also seems that the predicate True, even restricted to first-order sentences, is not expressible in the language of science. For the language of science is first order, whereas a truth predicate applicable to all first-order sentences cannot be expressed in a consistent first-order language, for Tarskian liar-based reasons.
One might try to get around this with a deflationary theory of truth, but deflationary theories of truth tend not to allow “True” to figure in explanations.

In my first comment I suggested that the crucial premise in the Plantinga style argument is the following: (3) if evolution is unguided by a supernatural agent (etc.) AND there is no other reason to think that our cognitive faculties are reliable, then we have no more reason to believe that they are reliable than that they are not. And then I argued that THERE IS other reason to think that our cognitive faculties are reliable. Alexander does not deny this. That claim will be enough to block drawing the conclusion: (1) if evolution is unguided by a supernatural agent (in particular, by God), then we have no more reason to believe that our cognitive faculties are reliable than that they are not. So no reason to think that naturalism leads to skepticism or is self-defeating.
So there is no reason to doubt that we can use our cognitive faculties to determine empirically whether some specific belief-desire mechanisms are reliable or unreliable. And it better be possible for there to be good evidence that certain mechanisms or systems in creatures are reliable because, intuitively, it’s possible for us to be justified in believing that this person’s immune system is a reliable protection against disease while that other person’s is not. No reason has been given why we must be skeptical about reaching conclusions about the reliability of certain cognitive-conative mechanism based on empirical evidence.